The present disclosure relates to a coil device used for wireless power transmission, a wireless power transmitter and a wireless power receiver having the same.
Electric and electronic devices are devices operated with electricity as the energy source thereof.
In order to operate an electric or an electronic device, electrical power, the energy source necessary to operate the device, has to be supplied thereto from the outside, unless the device has self-power generation capability.
Accordingly, in order to receive power from the outside, it is necessary for the electric or the electronic device to be equipped with a power transmission means to deliver power from an external power utility facility to the device.
Incidentally, wireless charging technology refers to a technology that transmits power for charging a battery wirelessly, without using a power cord or a connector for charging.
Previously, wireless charging technology has seen limited use, commonly in devices such as electric toothbrushes, home cordless telephones, and power tools.
Recently, due to explosive growth in the smartphone market, wireless charging technology has rapidly become widespread. Smartphones allow users to enjoy rich content and multimedia services anywhere and at anytime, but they suffer from short usage times, due to limited battery capacity.
Among other methods, a common means of realizing wireless charging is to use magnetic inductance or magnetic resonance, which uses electromagnetic energy coupling generated in a coil wound a number of times, as disclosed in the patent document below.
This is implemented as a device which is operated based on Faraday's law of induction; in which an electromagnetic field generated by a coil in which alternating current (AC) power or high-frequency current is flowing induces electromotive force at the output terminal of an adjacent coil. When a typical mobile phone, a smartphone, a digital camera, a tablet PC, a monitor, a laptop computer or the like, having a wireless charging receiver module embedded therein, is placed on a charging surface of a wireless charger having a wireless charging transmitter module configured therein, an analog circuit, a power circuit, a control circuit, a rectifying circuit, a charging circuit and the like, associated with charging, may be operated so as to charge a battery embedded in the device.
However, such a wireless charger may have a relatively large volume, and thus it may be inconvenient to store and carry, and it may be difficult to wirelessly charge several devices simultaneously therewith.